Currently we make a list of pages and functions. Then we guess how many hours are needed for design/development for each step OR pull up our time tracking of a similar job to calculate hours. We add a bunch of hours for UX and then just multiply that by an hourly rate and hope we can meet the budget. Is this what everyone else does too? How would you quote a 100 page website - existing, low conversion, poor design. Currently on Drupal - moving to Wordpress.
If you're interested in a different viewpoint all together, I would be able to tell you about how we sell Scrum without Waterfall. We don't ever have to fixed-bid anything. I generally find that fixed-bid is a solid way to lose your shirt.